1. Field of the Invention
The present invention is aimed at welding electrical conductors such as flexible or rigid metal bands to substrates such as direct bonding copper (DBC) insulated metal substrates.
Because the conductors carry high currents, their composition is generally based on copper.
2. Description of the Prior Art
A number of techniques have been used for welding conductors to substrates. Electric welding has been tried but proves to be very difficult because the heating is insufficient because of the very high electrical conductivity of copper. To remedy this drawback, consideration has been given to using tungsten electrodes, which generate a strong heating effect when current flows; heat from the electrodes propagates quickly into the copper parts to be welded, which increases the electrical resistance of the copper.
Electron column welding has also been used, but can only be carried out in a vacuum and continuously. Also, this method demagnetizes adjacent parts.
The present invention is aimed at a method and at equipment which remedy these drawbacks.